Solve Quartic with Casio FX-115MS
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09-02-2019, 02:35 PM
(This post was last modified: 09-02-2019 02:37 PM by Albert Chan.)
Post: #6
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RE: Solve Quartic with Casio FX-115MS
(08-30-2019 02:02 PM)Albert Chan Wrote: An old algorithm for solving Quartics: Brown's method ... To show AY/2 trick work, let roots, [c1,c2] = [p+q, p-q], [d1,d2] = [r+s,r-s] C = c1 d2 + c2 d1 = (p+q)(r-s) + (p-q)(r+s) = (pr - ps + qr - qs) + (pr + ps - qr - qs) = 2pr - 2qs = 2(A/2)(Y/2) - 2qs = AY/2 - 2qs If AY/2 = C, then 2qs = 0, sort order does not matter. If AY/2 > C, then 2qs > 0, thus c,d roots sorted the same way. If AY/2 < C, then 2qs < 0, thus c,d roots sorted opposite way. |
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Messages In This Thread |
Solve Quartic with Casio FX-115MS - Albert Chan - 11-29-2018, 05:28 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 11-29-2018, 10:31 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 02-04-2019, 01:39 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 08-24-2019, 12:47 PM
RE: Solve Quartic with Casio FX-115MS - SlideRule - 03-14-2020, 01:28 AM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 08-30-2019, 02:02 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 09-02-2019 02:35 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 02-01-2020, 12:27 PM
RE: Solve Quartic with Casio FX-115MS - Albert Chan - 03-13-2020, 06:30 PM
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